<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        .container {
            border: 1px solid red;
            width: 500px;
            margin: 0 auto;
        }

        .item {
            height: 60px;
            background: blue;
            width: 300px;
            margin: 50px auto;
        }
    </style>
</head>
<body>
<div class="container">
    <div class="item"></div>
    <div class="item"></div>
</div>
</body>
</html>